1. Field of the Invention
This invention relates to a flywheel assembly, and more particularly to a flywheel assembly for recording and or reproducing devices which is almost free from wow and flutter and extremely stable in balance during rotation.
2. Description of the Prior Art
In recording and or reproducing devices such as a tape recorder, a car stereo, etc., recording and or reproducing is usually achieved by driving a record medium such, for example, as a magnetic tape, or the like across a magnetic head. In such recording and or reproducing devices, the tape translation speed is liable to change to vary the recording and or reproducing frequency, causing wow and flutter which is a phenomenon peculiar to the recording and or reproducing devices. To avoid such a phenomenon, many efforts have heretofore been made.
A tape drive system usually employed in the recording and or reproducing devices is one that the tape is driven by the rotation of a capstan. With this system, a pinch roller is urged against the capstan whose peripheral speed is substantially equal to the tape translation speed and the tape is gripped between the pinch roller and the capstan and driven at a constant speed. In this case, the irregularity of rotation of the capstan gives rise to variations in its peripheral speed, resulting in fluctuation of the tape translation speed. The irregularity of rotation of the capstan is caused not only by eccentricity of its center of rotation but also by deficiencies of driving and power transmission parts such as variations in the rotation of a drive motor, irregularity of hardness of a belt and an idler, etc.
To prevent such irregularity of rotation of the capstan, it is the practice in the art to drive the capstan through a flywheel having sufficient moment of inertia to absorb the irregularity of rotation. In such a case, however, if the flywheel lacks balance and has no sufficient moment of inertia, the irregularity of rotation of the capstan is rather increased.